maybe tech-userlevel...
Due to my IPv6 changes, /etc/netstart requires /usr to be mounted.
This is because I used sysctl to check for IPv6 support. I would
like to avoid this and make mount of /usr to be optional as before.
What is the best way to check for kernel's capability of doing IPv6
(or random other protocol families, like appletalk)?
I can think of several candidates:
- use /sbin/ifconfig and some other tools. I may need grep, head, tail
and some other things but they are in /usr.
- add a tool that does
if (socket(AF_INET6, SOCK_RAW, 0) < 0)
exit(1);
else
exit(0);
into /sbin.
- assume that everybody has "options INET6" turned on.
but does not seem to be the best route. If you have a good way to
do this, please let me know.
itojun